I noticed several items that are not obtainable before future phases mentioned in different threads - all cluttered. So maybe we can collect them here in one single thread.
I noticed the following (suggested for locks):
Diana’s Pearl Necklace - P5
Don Mauricio’s Band of Domination - P5
Draconic Infused Emblem - P5
Dragonskin Cowl - P5
Spellweaver’s Turban - P5
Thuzadin Mantle - P5
Faith Healer’s Boots - P5
The catch-up gear added in 1.10 won’t be available until Phase 5.
Hope this helps 
@renrico I’m looking into the item source data. I have some proof that items are dropping that are listed as P5 on wowhead, but Blizzard said they’d be available in P1. For example, soot encrusted footpads, someone sent me information that their character has that item. I have this for several other p5 catchup items.
So we have all of those items listed as P1.
And then there is that thread you linked, which is confusing me. It seems like the sources are conflicting, saying catchup won’t be available until p5, and others saying it will be p1. That or I’m tired and my reading comprehension is shot.